Gear



Patented Nov. 30, 1920.

I l Illllll UNITED" STATES PATENTOFFICE.

FRANK r. B AL or nn morr, MICHIGAN, ASSIGNOR To rAoKArtDi/ro'rort oAaoou PANY, or nnraorr, MICHIGAN. A CORPORATION. or MICHIGAN.

Original application filediiecembr 23, 1914, Serial No. 878,733. Divided and this application filed April 29, 1918. Serial No. 231,422.

Toallwhomitmay concern: 7

Be it known that I, FRANK F. BEALL, a

citizenof the United States, and resident of division of applicafiled December 23,

7 formed by pressing or forging as distinguished from cutting or casting.

()ne objectof this invention is to provide gears having teeth denser at and adjacent the faces than elsewhere.

Another'object of. his invention is to provide gears having teeth the faces of which are compressed and die finished and the tops of which have a cut finish.

Other objects ofthe invention will appear from the following description, taken in connection with the drawings which form a part of the specification and in which Figure 1 is a part elevation and part section of a gear blank in the form in which it leaves the drop hammer;

Fig. 2 is a similar view of the'blank after leaving the roughing die;

Fig. 3 is a similar view of the blank after leaving the finishing die and before the excess metal hasbeen removed;

Fig. 4 is a similar view of the finished gear; i

Fig. 5 is a plan view of half of a finished 7 gear like that shown in Fig. 4:;

Fig. 6 is a fragmentary enlarged end elevation of several of the teeth of the finished gear showing in dotted lines the contours of the teeth in various stages of completion; and

Fig. 7 isan enlarged sectional view of the finished gear showing in dotted lines the contours of a tooth in various stages of completion.

This invention involves die pressing a blank to form teeth by displacing the metal of the blank with space forming die parts so that metal extends beyond the normal limits, as the tops, for instance, of the teeth, and then removing the excess, as by grinding or machining. The blank may be so This invention relates to gears and. gear manufacture and particularly to gears supported that: some excess metal will be pressed outwardly at the ends of the teeth, and this excess metal may likewise be removed.

The invention also involves die pressing a blankhaving teeth of abnormal proportions so that the teeth arepresse'd into the desired,

shape. As illustrated herein, a blank having teeth of abnormal thickness is die pressed so that the sides of the teeth are compressed to the desired face contour. The abnormally thick teeth may be formed by forging or die pressing with a roughing die. g In the form of theinvention particularly set forth herein, a gear blank having a plain fa ceis' drop forged, is then placedin adie 'presswhere a roughing die forms teeth of abnormal thickness and preferably of less height than the required finished tooth, is then subjected to a second die pressing .operation in which a finishing die compresses the thick teeth to the desired contour and forces excess metal outwardly beyond the normal tops and perhaps at the ends of the teeth, and is then machined or ground to remove the excess metal. The last step is the hardening of the finished gear. Gears made by this method will be found in most cases to be accurate enough for the finest work, but if desired a finishing cut may be made on the faces of the teeth before hardeningto give a still greater degreeof accuracy;

A gear made in; accordance with the above Specification of Letters Patent. Patented NO 30, 1920,

referred to methodis shown herein and comgenerally a gear blank and in Fig. 1 it is a plain blank 30 having a web portion 31 and a portion 32 in which the gear teeth are to be formed. In Fig. 2 the blank B is shown as having teeth 33 which are thick relative to the spaces between them and not as high as the teeth of the finished gear should be. As shown the teeth and spaces have no sharp corners it thereby being possible to form such a blank either by a quick rough pressing process or by drop forging. As shown also, the teeth are arranged in a generally diagonal direction and are curved lengthwise, but other desired forms of teeth may be made. 7 i r In Fig. 3 the gear blank B is shown as having its teeth 33 formed with correct faces 34 but an excess of metal extends above the normal tops of the teeth as shown at 35;

the dotted lines 35 representing the normal top of one of the teeth. Some of the excess metal has also been pressed outwardly at the ends of the teeth as at 36 and 37. Aside from the excess metal above referred to, the teeth of the gear shown in Fig. 3 are perfectly formed and would be ready for use.

In Figs. 4 and 5 the gear blank B has become a finished gear 38, the excess metal above referred to having been entirely removed either by machining or grinding, thus leaving a cut finish at the tops and on the ends of the teeth. In Figs. 6 and 7 enlarged views of gear teeth are shown, 35, 36 and 3'7 representing in dotted lines the excess metal that has been removed, and these views illustrate the clean sharp edges that are obtained by thus pressing the teeth and subsequently removing the excess metal. In thesefigures also the dotted line 39 traces an outline of the tooth 33 of the gear shown in Fig. 2 as it comes from the roughing die.

Ordinarily the gear thus completed will be sufficiently accurate for use, but if desired a machining or grinding process may be carried out on the faces of the teeth before it is case hardened. Case hardening gives the desired wearing qualities to the faces of the teeth and is particularly efficient when combined with the compressing of the gear teeth as herein described.

It will be understood that the invention is not limited to the specific gear herein shown and described, but is capable of modification in various ways without departing from the scope of the claims.

Having thus described my invention. What I claim and desire to secure by Letters Patent is I 1. A metal gear having teeth of denser formation at and adjacent the side faces than on the top surfaces therof.

2. A metal gear having teeth of denser formation at and adjacent the side faces than on the top and end surfaces thereof.

3. A metal gear having teeth, the faces of which have a die finish and the topsurfaces of which have a cut finish.

4. A metal gear having teeth, the faces of which have a. die finish and the tops and ends of which have a cut finish.

In testimony whereof I aflix my signature.

FRANK BEALL. 

